JPH09177961A - Lock-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable various kinds of cars to adopt a common automatic transmission by securing the fastening force of a lock-up means at the time of foot detaching. SOLUTION: In the case where a driver quickly lowers the engine throttle opening by detaching his foot, an automatic transmission control unit 30 heightens line pressure than an ordinary value to control the lowering of the fastening torque of the lock-up fastening element of a torque converter 11. But in the case when shift-up speed change is carried out with the rapid lowering of throttle opening, the line pressure is risen after the completion of speed change to suppress the increase of shift shock caused by the rising of line pressure during speed change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lockup device for directly connecting and rotating an input side and an output side of a fluid transmission device mounted on an automatic transmission.

[0002]

2. Description of the Related Art In an automatic transmission equipped with a fluid transmission device such as a torque converter, a lockup means for directly connecting and rotating an input side and an output side of the fluid transmission device is provided to prevent slip loss of the fluid transmission device during high-speed operation. Is avoiding. An automatic transmission is configured by combining a plurality of hydraulically actuated fastening elements (clutch, brake) with a shifting element such as a planetary gear device, and a hydraulic circuit incorporated in the automatic transmission is used as a fastening element or a lockup means. It includes a line pressure adjusting means for adjusting the supplied line pressure. The engagement element and the engagement force of the lockup means in the automatic transmission are set according to the throttle opening of the engine through the line pressure.

An example of a lockup device for setting the fastening force of lockup means provided in the torque converter according to the throttle opening of the engine is disclosed in Japanese Patent Laid-Open No. 62-8033.
No. 8 publication. Here, the line pressure is reduced when the throttle opening is reduced, but when the automatic transmission is operated in the D range (normal automatic shift mode) and the select operation is performed to the second speed range or the first speed range, Compared to the case where the D range is continued at the same throttle opening, the line pressure is increased to ensure that the fastening element or lockup means has a fastening force commensurate with the large engine braking torque that acts during the downshift. There is.

[0004]

By the way, when the driver releases the accelerator pedal during the operation of the D range with the lock-up means engaged, the lock force in which the engagement force is reduced due to the decrease in the line pressure. A considerably large engine braking torque acts on the fastening surface of the up means. In particular, in the case of going down a long downhill in a state where the legs are separated, a large load state of the fastening surface continues for a long time. Therefore, even in such a case, structural measures such as setting the fastening surface as close to the outer peripheral side as possible so that the fastening surface does not slip and increasing the fastening area and the pressure receiving area of the supplied hydraulic pressure are made. If slippage occurs on the fastening surface in the fastening state,
This is because the service life of the fastening surface may be impaired.

Further, the lock-up means provided in the torque converter normally carries out torque transmission between the engine and the speed change mechanism with a single engagement surface, and the load on the engagement surface is originally large, and the transmission speed is changed. It is not easy to reduce the load on the fastening surface by using multiple plates like other fastening elements of the mechanism.
Therefore, there are cases where the same automatic transmission cannot be used for different vehicle bodies and vehicle types due to insufficient fastening force of the lock-up means when the foot is released.

For example, when the weight of the loaded cargo is large, the engine braking torque that the fastening surface of the lock-up means bears when the legs are released is larger than when the cargo is empty. Therefore, it may not be possible to adopt the same automatic transmission and torque converter as parts for a heavy-duty truck in a heavy-duty truck. Also, in trucks equipped with exhaust brakes, the exhaust brakes are activated by detecting foot release.However, when the exhaust brakes are activated, the rotational resistance of the engine suddenly increases, and the fastening surface of the lock-up means becomes a burden. The engine braking torque that is applied also increases. Therefore, it may not be possible to adopt the same automatic transmission or torque converter as a part of a truck that does not have an exhaust brake.

It is an object of the present invention to provide a lock-up device in which the fastening force of the lock-up means at the time of foot release is secured and a common automatic transmission and a common torque converter as a component can be adopted in a wide variety of vehicle types. I am trying.

[0008]

According to a first aspect of the present invention, there is provided a line pressure adjusting means for adjusting a line pressure supplied to a fastening element of an automatic transmission, and a fluid transmission device with a fastening force corresponding to the line pressure. A lockup device having lockup means for directly connecting and rotating an input side and an output side, and a control means for controlling the line pressure adjusting means to set the line pressure according to an engine throttle opening, Means, detecting means for detecting that the amount of depression of the accelerator pedal by the driver is less than or equal to a predetermined value, and the above when the amount of depression is less than or equal to a predetermined value in the engaged state of the lockup means. And a means for increasing the line pressure.

According to a second aspect of the invention, the premium means in the structure of the first aspect is an identification means for identifying whether or not the automatic transmission is undergoing gear shifting, and, if the gear shifting is underway, waiting for completion thereof. Standby means for executing the additional increase of the line pressure.

According to a third aspect of the present invention, the standby means in the second aspect executes the additional increase of the line pressure after a lapse of a predetermined time from the determination of the shift.

[0011]

According to the lock-up device of the present invention, when the driver reduces the depression amount of the accelerator pedal to a predetermined value or less, the line pressure is increased and the lock-up is increased as compared with the case where the driver exceeds the predetermined value. Increase the fastening force in the means. Therefore, even if the amount of depression of the accelerator pedal falls below a predetermined value and a large engine brake torque is applied,
Compared to the case where the line pressure is not increased, slippage is less likely to occur on the fastening surface.

According to another aspect of the lock-up device of the present invention, when the driver makes a shift decision when the accelerator pedal depression amount is reduced to a predetermined value or less, the line pressure is increased after waiting for the shift completion. Let Therefore, the line pressure is not increased during the shift, and the engagement states of the plurality of engagement elements of the automatic transmission are recombined under normal line pressure control in which the increase is not increased.

In the lock-up device according to the third aspect, instead of detecting the completion of the shift from the actual measured value of the gear ratio or the like, the time when the timer for a predetermined time started at the time of judgment of the shift is up is regarded as the completion of the shift. , Execute extra line pressure.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The lockup hydraulic pressure control during coasting of the embodiment will be described with reference to FIGS. FIG. 1 is an explanatory diagram of a line pressure control system, FIG. 2 is a time chart of line pressure control, FIG. 3 is an explanatory diagram of shift-up shifting, and FIG.
Is a diagram of line pressure control, and FIG. 5 is a flowchart of control of the embodiment. In FIG. 1, the automatic transmission of the embodiment is
The engine output input through the torque converter 11 is shifted by the transmission mechanism 12. The speed change mechanism 12 includes a plurality of engagement elements (clutch and brake) not shown. These engagement elements are hydraulically controlled through the hydraulic circuit 21, and a predetermined shift-down shift or shift-up shift is executed by changing the combination of the engagements.

The torque converter 11 is provided with a lock-up fastening element (clutch) 22 inside its shell structure. When the lockup engagement element 22 moves to the left side in the figure and is pressed against the shell structure of the torque converter 11, a lockup state is established, and the engine output is directly shifted from the shell structure of the torque converter 11 via the lockup engagement element 22. Input to the mechanism 12. On the other hand, in the non-lockup state, the lockup fastening element 22 moves to the right side in the drawing and is held in non-contact with the shell structure of the torque converter 11, so that the power transmission via the fluid by the oil inside the torque converter 11 is performed. Becomes

The lockup control valve 13 is
For example, NISSAN Automatic Transmission Maintenance Manual RL4R01A type (issued March 1989)
As described in (1), the relationship between the hydraulic pressure supply and the hydraulic discharge to the relief chamber 28 and the apply chamber 29 of the torque converter 11 is switched to control the lockup state and the non-lockup state (including the transient state).

In the lock-up state, the torque converter apply pressure supplied through the oil passage 27 is supplied to the apply chamber 29 through the lock-up control valve 13 as shown, while the relief chamber 28 is supplied.
Oil is discharged through the drain 26. In the non-lockup state, the same torque converter apply pressure is supplied to the relief chamber 28 through the lockup control valve 13, the oil in the apply chamber 29 is cooled through the oil cooler 24, and then the rear portion of the transmission mechanism 12 (on the output shaft side). It is discharged to the rear lubrication 25 that lubricates the (part). The torque converter apply pressure is also branched and supplied to the front lubrication 23 that lubricates the front portion of the transmission mechanism 12 (torque converter side portion).

The line pressure supplied to the fastening elements of the speed change mechanism 12 through the hydraulic circuit 21 is formed in the oil passage 31 by controlling the oil pump 19 with the pressure regulator valve 15. The pilot valve 18 is the oil pump 1
9 always forms a constant pilot pressure from the line pressure output to the oil passage 31. The automatic transmission control unit (ATCU) 30 controls the ON / OFF duty ratio of the line pressure solenoid 20 according to the throttle opening of the engine to form the throttle pressure from the pilot pressure, and inputs the throttle pressure to the pressure modifier valve 16. .

The pressure modifier valve 16 is
The pulsation of the throttle pressure is removed, and the pressure modifier pressure corresponding to the throttle opening is formed from the pilot pressure. The modifier accumulation valve 17 moderates the pressure fluctuation of the pressure modifier pressure input to the pressure regulator valve 15. The pressure regulator valve 15 forms an oil pump feedback pressure according to the pressure modifier pressure and inputs it to the oil pump 19 from the oil passage 32. The oil pump 19 outputs a discharge amount according to the oil pump feedback pressure. The line pressure rises and falls according to this discharge amount with respect to the total resistance load connected to the oil passage 31, and is maintained. Automatic transmission control unit 30
The line pressure in the oil passage 31 is adjusted as shown by the solid line in FIG. 4 in accordance with the throttle opening degree of the engine through the series of hydraulic pressure control that is started by the control of the line pressure solenoid 20.

The line pressure supplied to the fastening elements of the speed change mechanism 12 is used up to a considerably high pressure, but the torque converter 11 cannot bear a large pressure because it has a relatively thin shell structure. Therefore, a part of the line pressure of the oil passage 31 is supplied to the torque converter relief valve 14 through the pressure regulator valve 15,
In the torque converter relief valve 14, it is converted into a torque converter apply pressure that is one step lower than the line pressure. Torque converter relief valve 14
Is discharged from the oil passage 33 at a portion exceeding a certain pressure,
The torque converter apply pressure changes according to the throttle opening, as shown by hatching in FIG. In the range of the torque converter apply pressure limited by the torque converter relief valve 14, the lockup fastening element 2
2 bears the engine braking torque associated with the release of the foot.

The tightening torque Q of the shell structure of the torque converter 11 and the lock-up fastening element 22 is calculated by using the torque converter apply pressure Pa, the pressure-receiving area A of the lock-up fastening element 22, the friction coefficient μ, and the effective facing diameter D. = Μ × D × A × Pa. Therefore, if the driver is in the lock-up state when he / she depresses the accelerator pedal to enter the coast state, the line pressure decreases as the throttle opening decreases, so the engine rotational resistance increases and lock-up occurs. While the engine braking torque that the fastening element 22 bears increases, the fastening torque Q of the lockup fastening element 22 decreases.

On the other hand, the automatic transmission control unit 30 detects whether or not the idle switch of the throttle sensor is ON (corresponding to a predetermined value of the throttle opening or less), and determines whether or not the foot is released. When it is determined that the line is released, the backup control is started to keep the line pressure high. As a result, the torque converter apply pressure P
a is maintained high, and the reduction of the fastening torque Q of the lockup fastening element 22 is suppressed. FIG. 3 shows a shift-up shift timing and a lock-up timing. Shift line L1
1-2 shift line, shift line L2 2-3 shift line, shift line L
3 is a 3-4 shift line. Then, when the combination of the vehicle speed and the throttle opening exceeds the lockup line L4, the non-lockup state is changed to the lockup state. It is assumed that the driver releases the foot in state C while traveling at the fourth speed in the D range (overdrive gear) and the throttle opening sharply drops to state D. At this time, the automatic transmission control unit 30 immediately starts the backup control to increase the fastening force of the lockup fastening element 22.

In the conventional backup control disclosed in Japanese Patent Laid-Open No. 62-80338, when the driver operates the select lever to perform the select down operation from the D range to the second speed range or the first speed range, the automatic control is automatically performed. The transmission control unit increased the line pressure to increase the fastening force of the fastening elements of the transmission mechanism, and secured the fastening force commensurate with the large engine braking torque accompanying the downshift.

However, in the present embodiment, the backup control is extended and applied to the case where the select down operation is performed and also to the simple release of the foot without the operation of the select lever. Then, in order to ensure the quality of the shift-up shift accompanying foot release, when the shift-up shift (third speed-fourth speed) is judged at the time of foot release, the completion of the shift-up shift is waited as shown in FIG. Start backup control. For example, as shown in FIG. 3, it is assumed that the driver performs a foot release in a state E in which the vehicle is traveling at the third speed (direct connection stage) in the D range, and the throttle opening sharply drops to a state F. When the automatic transmission control unit 30 crosses the shift line L3, the automatic transmission control unit 30 determines a shift-up shift from the third speed to the fourth speed, and starts the shift operation to the fourth speed. At this time, as shown in FIG. 2, the timer for a predetermined time is started at the time A when the shift judgment is made, and the backup control is started from the time B when the timer is up so that the line pressure is hatched only at a portion higher than usual. Surcharge. As a result, the line pressure is increased as indicated by the arrow in FIG.
The torque converter apply pressure in the state F after the upshift is not lowered to the state G when the accelerator pedal is gently released, and is maintained at a level not much different from the state E immediately before the foot is released.

The automatic transmission control unit 30 includes
A number of processes for controlling the automatic transmission are performed, and the line pressure backup start process is performed as one of the interrupt processes as shown in FIG.
Follow the procedure shown in. In step 111, it is determined whether or not the driver has operated the select lever to select down.
The process proceeds to 15 to start the backup control (BU control). If it does not correspond to the select down, step 112
Proceed to.

In step 112, it is determined whether or not the changing state of the throttle opening every moment corresponds to the foot release. When it is determined that the foot is released, the routine proceeds to step 113, where it is determined whether or not the upshift is to be performed. If it is not determined that the foot is released, the interrupt process is completed and the process returns to the main program (not shown). When it is determined in step 113 that the shift-up shift is to be performed, the routine proceeds to step 114, where normal line pressure control (PL control) is started. In the normal line pressure control, after waiting for the timer started at the same time as the gear shift judgment to be started, the routine proceeds to step 115 after the gear shift is completed to start the backup control. If the upshift is not determined, the backup control is started immediately. In addition,
Detailed procedures (constant of control, timing of termination and interruption, etc.) in normal line pressure control and backup control are determined by a main program installed in the automatic transmission control unit 30 and other interrupt processing.

According to the line pressure control of the embodiment, when the driver releases the foot, backup control is applied to increase the line pressure to secure a high torque converter apply pressure. The fastening torque Q is maintained high and there is no concern that the lock-up fastening element will slip due to the engine braking force that accompanies the release of the foot. In addition, the backup control that is applied when the driver performs the select down operation through the select lever is extended to the state of foot release and applied, so there is no need to add wiring or sensors, and the conventional backup control is included. It can be implemented with only minor changes in the processing program.
Further, since the fastening torque Q of the lock-up fastening element 22 is increased by controlling the line pressure by the line pressure solenoid 20, it is not necessary to add a solenoid, a valve, or an oil passage, and wiring connected to the automatic transmission control unit 30 is required. There is no increase.

When it is determined that the shift-up shift is to be performed due to the release of the foot, the backup control is started after the shift is completed. Therefore, the line pressure does not increase before or during the shift, and the shift mechanism 12 It is possible to avoid a situation in which the clutches and brakes of 6 are shockedly engaged and a large shift shock is generated. Since the completion of the shift-up shift is determined by the timer, the automatic transmission having no sensor or processing for detecting the gear ratio can be used without increasing the number of sensors and wiring, and is mounted on the automatic transmission control unit 30. The addition of additional programs is minimal.

The lock-up fastening element 2 shown in FIG.
2 is the lockup means of the invention, the line pressure solenoid 2
0, the pressure regulator valve 15, the pressure modifier valve 16, the modifier accumulation valve 17, and the oil pump 19 correspond to the line pressure adjusting means of the invention, and the automatic transmission control unit 30 corresponds to the controlling means of the invention. In addition, step 1 shown in FIG.
12 is the detection means of the invention, steps 113, 114, 11
5 corresponds to the premium means of the invention, step 113 corresponds to the identification means of the invention, and step 114 corresponds to the standby means of the invention.

[0030]

According to the first aspect of the present invention, when the driver releases the foot, the line pressure is increased to increase the engagement torque of the lock-up means larger than usual. Therefore, the engine accompanying the foot release is increased. There is no concern that the lockup means in the lockup state will slip due to the brake. Therefore, it is not necessary to select the automatic transmission due to the possibility that the lockup means will slip, and the common automatic transmission can be used in a wide variety of vehicle types and applications. For example, a common combination of engine and automatic transmission can be adopted for trucks with different loadings and passenger cars with different body weights.

According to the second aspect of the invention, when the gear shift is executed with the release of the foot, the line pressure is increased after the gear shift is completed. Therefore, the line pressure is increased before or during the gear shift. Therefore, it is possible to avoid a situation in which the clutch or brake of the automatic transmission is shockly engaged to cause a large shift shock. Further, since the control of the automatic transmission relating to the gear shift can be executed in the same procedure and timing as the conventional one, the control of the automatic transmission does not become complicated.

According to the third aspect of the invention, the end of the shift is set to 1
Since it is detected by the individual timers, the number of parts and the increase of the control program can be reduced as compared with the case of determining the gear ratio. For example, a turbine sensor for detecting the turbine speed of the torque converter is unnecessary.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a line pressure control system.

FIG. 2 is a time chart of line pressure control.

FIG. 3 is an explanatory diagram of a shift-up shift line.

FIG. 4 is a diagram of line pressure control.

FIG. 5 is a flowchart of control of the embodiment.

[Explanation of symbols]

 11 Torque Converter 12 Speed Change Mechanism 13 Lockup Control Valve 14 Torque Converter Relief Valve 15 Pressure Regulator Valve 16 Pressure Modifier Valve 17 Modifier Accumulation Valve 18 Pilot Valve 19 Oil Pump 20 Line Pressure Solenoid 21 Hydraulic Circuit 22 Lockup Fastening Element 23 Previous Part lubrication 24 Oil cooler 25 Rear part lubrication 26, 27, 31, 32, 33 Oil passage 28 Apply chamber 29 Relief chamber 30 Automatic transmission control unit

Claims (3)

[Claims] 1. A line pressure adjusting means for adjusting a line pressure supplied to a fastening element of an automatic transmission, and a lockup for directly connecting and rotating an input side and an output side of a fluid transmission device by a fastening force corresponding to the line pressure. A lock-up device having means for controlling the line pressure adjusting means to set the line pressure according to the throttle opening degree of the engine, wherein the control means is the amount of depression of the accelerator pedal by the driver. Includes a detection unit that detects that the line pressure is less than or equal to a predetermined value, and a premium unit that increases the line pressure when it is detected that the depression amount is less than or equal to a predetermined value in the engaged state of the lockup unit. Lockup device characterized by. 2. The additional means is an identification means for identifying whether or not the automatic transmission is undergoing a shift operation, and a standby means for executing the extra line pressure after waiting for the completion of the shift operation during the shift operation. The lockup device according to claim 1, further comprising: 3. The lock-up device according to claim 2, wherein the standby means executes the premium of the line pressure after a lapse of a predetermined time from the determination of the shift.